DE102018100511A1 - Rotor blade for wind turbines - Google Patents

Rotor blade for wind turbines

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Publication number
DE102018100511A1
DE102018100511A1 DE102018100511.3A DE102018100511A DE102018100511A1 DE 102018100511 A1 DE102018100511 A1 DE 102018100511A1 DE 102018100511 A DE102018100511 A DE 102018100511A DE 102018100511 A1 DE102018100511 A1 DE 102018100511A1
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DE
Germany
Prior art keywords
rotor blade
characterized
preceding
wind
rotor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
DE102018100511.3A
Other languages
German (de)
Inventor
Anmelder Gleich
Original Assignee
Mehmet Güncü
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mehmet Güncü filed Critical Mehmet Güncü
Priority to DE102018100511.3A priority Critical patent/DE102018100511A1/en
Publication of DE102018100511A1 publication Critical patent/DE102018100511A1/en
Pending legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03DWIND MOTORS
    • F03D1/00Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06Rotors
    • F03D1/0608Rotors characterised by their form
    • F03D1/0633Rotors characterised by their form of the blades
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03DWIND MOTORS
    • F03D1/00Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06Rotors

Abstract

The invention relates to a rotor blade with a curvature, through which a suction effect or a negative pressure is created by the overflowing air, wherein the rotor blade is advantageously formed as a sub-segment of a concentric tube and tapers from the root end to its outer free end. It corresponds to the principle of an aircraft wing in take-off position.

Description

  • The invention relates to a rotor blade for wind turbines.
  • The use of wind energy is of particular importance in our latitudes, because it is available over a much longer period of time than the solar energy and thus requires less storage capacity. In addition, it has considerably more potential than hydropower. Wind turbines will therefore play a key role in the future supply of eco-energy. That is why research is being carried out into particularly efficient solutions. Depending on the task and size different requirements are to be considered. For example, in very large wind turbines, the wings must be composed of individual segments and be considerably lighter and stiffer than before. Partly the wings have to fold down in case of a storm. If the individual parts are particularly large, larger gears are needed to convert the low speeds and powerful torques into suitable generator speeds. For example, very large wind turbines may not make more than 16 revolutions per minute in order not to produce a sonic boom at the wing tips. Also, problems such as wake, trickle, pitch, thrust and chaotic meandering are to be overcome, as well as the ambient turbulence intensity on the windward side in closely spaced wind turbines.
  • From the DE 11 2012 005 432 T5 is a wind turbine for generating electrical energy using wind power, in particular a wind turbine with a gondola fence for improving the aerodynamic performance by the mounting of a Zaunstruktur on the gondola of a horizontal axis wind turbine known. The wind turbine with a gondola fence reduces the vortex generated at the downstream end of rotating blades so that the aerodynamic performance of the rotor blades is improved, thereby increasing the performance coefficient of the wind turbine.
  • The DE 10 2009 038 076 A1 discloses a rotor element for flowing around a fluid and for a rotor. It comprises a rotor blade which has two side surfaces, and a flow guide surface associated with the rotor blade, the wake of which at least partially influences the flow on one of the side surfaces of the rotor blade.
  • From the other DE 10 2012 209 935 A1 is a rear box for a rotor blade, in particular a wind turbine, comprising a pressure side surface, a suction side surface, a pressure and suction side surface separating trailing edge and a rear edge opposite connecting side, which is adapted for attachment to a corresponding connection surface of the rotor blade. In particular, this document relates to a rear box which is subdivided into a foot segment having the connection side and one or more rear segments having head segments which can be coupled to the foot segment. At the same time it relates to a rotor blade for a wind turbine.
  • The previously known rotor blades have in common that they have a more or less steep position of the rotor blades relative to the main wind direction. As a result, considerable pressure is exerted on the vertical axis of the rotor blades of the rotor and the wind turbine. The rotor blades also bend in the direction of their back, so the side facing away from the wind. This goes so far in part that the rotor blades pass close to the associated tower of the wind turbine.
  • In order to master the occurring problems, sometimes elaborate blade adjustment systems are required (see Joerg Karl Berroth: Influence of the dynamic response of the rotor blades on the loads of the pitch adjustment systems of wind turbines, August 2017).
  • In addition, load-reducing control concepts are developed to dampen the load dynamics directly on the rotor blade. These concepts are usually based on additional blade angle adjustment and thus additionally lead to increased demands on the pitch adjustment systems of wind turbines. Influences on the dynamic loads of the blade adjustment systems are also examined in order to obtain reliable load assumptions for the realization of highly dynamic blade angle adjustment for active load reduction.
  • In departure from the previous design of such rotor blades, the invention proposes flat rotor blades. At these, the wind almost unhindered, similar to the wing of an aircraft, strike past, while lifting the rotor blade on the bottom and on the top by the corresponding curvature exerts a negative pressure, so that the rotor blade lifts even more easily and in rotation added. The rotor blade thus advantageously has a curvature through which a suction effect or a negative pressure is created by the overflowing air. The passing air raises the rotor blade in relation to the generator axis. According to the Bernoulli principle, the air is compressed as it hits the front of the wing like a bottleneck and thus forced to flow faster. The thus resulting at the Rotorober- and -unterseite pressure difference generates the desired buoyancy.
  • The Coanda effect describes the working principle that air has a tendency to adhere to a surface and therefore to follow its curvature as it flows past. It follows that the air at the top of the wing is sucked down and thus creates a negative pressure above the wing.
  • Decisive for the desired buoyancy is not only the profile of the wing or rotor blade, but its angle of attack. A tilted wing pushes the air down by applying force to it. This, according to Newton's law "actio = reactio", at the same moment produces an opposing force which pushes the wing or the rotor blade upwards.
  • According to rough calculations, the resulting force under the wing or the rotor blade accounts for about one third of the total lift, the remaining two-thirds come from the suction that prevails at the top. The curvature of the wing or rotor blade is not critical to buoyancy, although it can improve it. However, a flat wing also creates buoyancy. Important is the angle of attack, that is the angle at which the wing stands to the air flow. With constant air density, blade size, blade pitch, and constant pitch, the buoyancy force is proportional to the square of the airspeed. Both the deflected air per unit time and its vertical acceleration grow proportionally with the air velocity. At double air speed and otherwise the same air flow doubles up both the accelerated air down, as well as their speed. This means that the lift quadruples. Since the deflection speed and the drive power required for it is quadratic, the power required for the lift generation is inversely proportional to the air speed and the size of the wings or rotor surfaces. This means that the higher the air speed or the larger the rotor blades, the greater the turbine power. This mechanism of action is part of the induced resistance. It removes the buoyancy of the energy required by the flow systems in the form of flow resistance.
  • The Coanda effect can ensure the flow at the top of the wing or rotor blade only up to a certain, depending on the profile shape, the surface quality and the Reynolds number attack angle. This is usually about 15 - 20 percent. Beyond this angle of attack, the flow breaks away from the surface. This causes a drastic increase in the shape resistance, at the same time breaks the greater part of the lift together, since the profile in this flow state to the air flow
    the top of the wing or rotor blade can no longer effectively distract, but essentially only swirled.
  • In order to achieve a better buoyancy distribution and thus a lower induced resistance, the rotor blades according to the invention are elongated and taper in the outer region, so have an escalation. The length is advantageously six times a quarter of the circumference, ie the tube from which they are cut.
  • With the rotor blades according to the invention previously generated vortex are avoided or reduced, and improves the aerodynamic performance of the rotor blades and thus increases the power coefficient of the wind turbine surprisingly significant. Thus, it is possible to use the kinetic energy of the wind with the highest possible efficiency. The rotors are designed with a substantially horizontal axis of rotation, have at least two adjustable rotor blades and generate a torque on a shaft, which is used via a transmission for driving an electric generator. Depending on the size, in particular height, and the length of the rotor blades, there are different performance classes. The design of wind turbines is based on the Betz formula; then only about 60% energy can be taken from the passing wind, otherwise the wind will be slowed down too much or the wind will wind around the windmill evasively.
  • Even the most modern wind converters can not convert 100% of the theoretical Pth power contained in the wind. Since the air behind the windmill still has to flow away at a certain speed, the wind can not be completely decelerated, so that a part of the kinetic energy remains. The theoretical optimum, which can be calculated by means of formulas, by calculating the ratio of wind velocities before and after the converter vanes, in which a maximum of energy is withdrawn from the flowing air, is achieved when the wind speed in the wind wheel plane two-thirds is reduced, behind the wings so still has a third of the original speed. The energy yield can then be theoretically exactly 16 / 27th, that is about 60% of the total energy contained in the wind, provided that the wind turbine has the ideal wing for the design speed. Good, technically feasible wings convert instead of the theoretically calculated 60% so far around 40% of the total energy contained in the wind. Ideal wings can be made just as practical, as in reality the wind blows for a long time at design speed. Basic Information can be found in the book by dr. Albert Betz, wind energy and its use by windmills, first published in 1926 and today available as a reprint at Ökobuch Verlag, Staufen.
  • Further theoretical foundations can be found in the book by Karl Bielau: Wind power in theory and practice from 1925.
  • Both were based on the realization that the wings withdraw energy from the wind. To do this, they have to be designed in a very specific way. For their design, the theory of aerodynamics provides the scientific basis: In any case, the wing cross-section must be a buoyancy profile. The force that pushes back the rotor blade, which thus acts parallel to the flow, is called resistance force, and that force acting perpendicular to the flow, buoyancy force.
  • Has a ruler-like body with a certain length, the span, and a certain width, the depth, a low resistance to the direction of movement and a high buoyancy perpendicular to the flow direction, so it is called wing. Such a bird's wing usually has a thickness that is small relative to the depth. The wing also denotes the main purpose of use. It finds practical application in every airplane and every wind turbine wing.
  • The largest buoyancy force develops at a certain angle of attack, which forms the center line of the profile with the flow direction. An important angle of attack is one in which the quotient of buoyancy force and resistance reaches a maximum. This quotient is called the glide ratio. The higher the glide ratio of the windmill profile, the better the energy yield. In the polar diagrams used in practice, the buoyancy and drag coefficients are plotted for various angles of attack. These coefficients are determined experimentally and are also based on the flow velocity
  • dependent. If the angle of attack becomes too great, the flow on the top swirls - this is the leeward side of the profile for the wind turbine blade - and becomes turbulent. In this state, the buoyancy force collapses and the resistance force increases sharply.
  • If this transition into turbulence - compared with other profile cross sections - only at large angles of attack, one speaks of a good-natured profile. The faster a profile flows around, the more the surface roughness influences the size of the resistance and the turbulence envelope. How the buoyancy force arises has always been evident from measurements of the pressure differential between the upper and lower sides of the profile. The results show that the print side down, i. at the wind turbine wing in windward, and the suction side above, that is the wind turbine wing in lee.
  • The size of the pressure difference on the one hand and the dimensions of the wing on the other hand allow overcoming the weight of a flying aircraft. When the wind flows around a rotor, it also generates a force comparable to that on the wing. In the wind converter, it is used to generate a torque at the rotor axis. Since the suction side is particularly turbulence-sensitive, it must be very carefully executed and smoothed. Every little tripping edge makes itself noticeable as a loss of flow in terms of energy yield, and even more so the higher the number of revolutions. Slow rotating rotors are more stable in flow. (see Horst Crome, manual wind energy technology, wind turbines in craft production, Ökobuch Verlag, Staufen 4th edition 2012).
  • In principle, in power generating wind turbines, high lift profiles with a very favorable ratio of lift and drag coefficients, i. a high glide ratio, preferred. Especially in the area of the blade tip, a high glide ratio plays a primary role, which requires thin profiles. Due to the high rotational speed, a short tread depth is sufficient. Indoors, due to lower peripheral speed, the local speed of rotation and the flow velocity are significantly lower. This requires equally large buoyancy forces the larger tread depths and also allows the use of thicker profiles than in the outdoor area. However, it is not inevitable that different profiles are used outdoors or indoors, although at the blade root, the largest loads occur, so that thicker profile meet the strength requirements.
  • For slow-running rotors simple profiles of bent steel sheets are realized, while in rotor blades of high-speed power generating wind turbines, the demands on the profiles are higher. These are mainly laminated from glass fiber and carbon fiber reinforced plastics (GRP or CFRP). Carbon fibers have up to 3 times higher static strength and, in addition, tend to have higher fatigue strengths.
  • Traditionally, separate wing shapes for the suction and pressure side are lined with fibrous webs and then impregnated with polyester or Expozidharz. Some fiber fabrics are also pre-soaked. Sometimes, the so-called sandwich construction is preferred in the a balsa wood layer lies between the outer and inner fiber layer. By a predetermined heating, the resin is cured and then the wing halves are glued together. The form- and strength-giving profile shells of the GRP wings are then still filled with foam and / or stiffened by GRP webs. The sheet is coated with weather and UV resistant coating from the outside. In order to avoid material removal at the leaf leading edges erosion protection foils are glued on, which can be exchanged if worn. In addition, flow elements can be applied to the vanes, for example so-called "vortex" generators, which in operation provide for defined flow states and guidance despite the wind speeds fluctuating with the rotor circulation and the time.
  • (See Robert Gasch, Jochen Twele (Hrsg) wind turbines, fundamentals, design, planning and operation, Springer Vieweg Verlag, 8th Edition 2013).
  • In an embodiment, the rotor blade according to the invention is designed as a sub-segment of a concentric tube. It may taper from the root end to its outer free end and correspond approximately 1/3 of a concentric tube at the root end and approximately 1/12 of the concentric tube at its outer, free end.
  • It is also envisaged that the rotor blade tapers from its root end linearly towards its free end.
  • Furthermore, it is provided in an advantageous embodiment that the viewed in the direction of rotation of the upper edge of the rotor blade extends from the root end perpendicular to its free end and extends at an acute angle at its lower edge.
  • The rotor blade is in particular modeled on an aircraft wing and extends at its root end from the upper edge at an angle of 30 ° to 60 ° to its lower edge.
  • The invention is explained below with reference to the drawing. This shows in
    • 1 a perspective view of a three-bladed windmill rotor blades according to the invention
    • 2 a detailed view according 1
    • 3 a detailed view of a rotor blade
    • 4 a detail view of a rotor blade rotated by 180 °
    • 5 a detailed view of a plurality of rotor blades arranged on a rotor hub
    • 6 an alternative view too 5
    • 7 a further detailed view of the arrangement of a plurality of rotor blades on the rotor hub
    • 8th another view of 7
    • 9 a planar development of a rotor blade according to the invention
    • 10 a schematic diagram of a rotor blade at its root end
    • 11 a schematic diagram of a rotor blade at its free end
    • 12 A plan view of an inventive rotor blade
    • 13 An enlarged section according to 12
    • 14 A perspective view of an inventive rotor blade
  • A rotor blade 1 , such as from the 14 , but also from the 12 - 13 and from the 3 - 4 shows, has a uniform curvature and is formed as a sub-segment of a concentric tube from which it can be cut. This curvature creates a suction effect or a negative pressure due to the overflowing air, so that this total air flowing past the rotor blade 1 in relation to the generator axis 2 lift and spin. The rotor blade 1 rejuvenates from its root end 3 towards his outer free end 4 , being at its root end 3 approximately one third of a concentric tube and to an outer free end 4 approximately one twelfth of the concentric tube corresponds, see. 10 - 11 that represent this in principle.
  • The upper edge seen in the direction of rotation 5 of the rotor blade 1 extends from the root end 3 right-angled to its free end 4 down while its bottom edge 6 at an acute angle there. In particular, the rotor blade runs 1 at its root end 3 from the top edge 5 at an angle of 30 ° to 60 ° to its lower edge 6 ,
  • The length of the rotor blade 1 may advantageously correspond to six times a quarter of the circumference of a concentric tube from which the rotor blade 1 is cut out.
  • The rotor blades 1 are exemplary by connecting means 7 , about right-angled attachment pieces 7 , with the generator axis 2 connected, the drawing in each case three rotor blades 1 per generator axis 2 provides. But it is also conceivable that only two rotor blades 1 are present, as well as the number of rotor blades 1 if necessary also increased become. A planar development of the rotor blade 1 is in 9 shown.
  • Of course, the invention is not limited to the illustrated embodiments. Further embodiments are possible without departing from the basic idea. It is only important that the rotor blade is designed so flat that the wind almost unhindered past him, but at the same time raise it by the resulting pressure and suction effect and the rotor can set in motion.
  • QUOTES INCLUDE IN THE DESCRIPTION
  • This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
  • Cited patent literature
    • DE 112012005432 T5 [0003]
    • DE 102009038076 A1 [0004]
    • DE 102012209935 A1 [0005]

Claims (11)

  1. Rotor blade (1) for a generator, in particular for a wind energy plant, characterized in that the rotor blade (1) is formed flat.
  2. Rotor blade after Claim 1 , characterized in that the rotor blade (1) has a curvature, through which a suction effect or a negative pressure is created by the overflowing air.
  3. Rotor blade after Claim 1 or 2 , characterized in that the air flowing past the rotor blade (1) in relation to the generator axis (2) lifts.
  4. Rotor blade according to one or more of the preceding claims, characterized in that the rotor blade (1) is designed as a sub-segment of a concentric tube.
  5. Rotor blade according to one or more of the preceding claims, characterized in that the rotor blade (1) tapers from the root end (3) towards its outer free end (4).
  6. Rotor blade according to one or more of the preceding claims, characterized in that the rotor blade (1) at the root end (3) approximately corresponds to 1/3 of a concentric tube and at its outer, free end (4) approximately 1/12 of the concentric tube (7 ).
  7. Rotor blade according to one or more of the preceding claims, characterized in that the rotor blade (1) tapers from its root end (3) linearly towards its free end (4).
  8. Rotor blade according to one or more of the preceding claims, characterized in that the upper edge (5) of the rotor blade (1) seen in the direction of rotation extends from the root end (3) at right angles to its free end (4) and at its lower edge (6). runs at an acute angle.
  9. Rotor blade according to one or more of the preceding claims, characterized in that the rotor blade (1) is modeled on an aircraft wing.
  10. Rotor blade according to one or more of the preceding claims, characterized in that the rotor blade (1) extends at its root end (3) from the upper edge (5) at an angle of 30 ° to 60 ° to its lower edge (6).
  11. Rotor blade according to one or more of the preceding claims, characterized in that the length of the rotor blade (1) corresponds to six times a quarter of the circumference of a concentric tube (7), from which the rotor blade (1) is cut.
DE102018100511.3A 2018-01-11 2018-01-11 Rotor blade for wind turbines Pending DE102018100511A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE102018100511.3A DE102018100511A1 (en) 2018-01-11 2018-01-11 Rotor blade for wind turbines

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102018100511.3A DE102018100511A1 (en) 2018-01-11 2018-01-11 Rotor blade for wind turbines

Publications (1)

Publication Number Publication Date
DE102018100511A1 true DE102018100511A1 (en) 2019-07-11

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Family Applications (1)

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DE102018100511.3A Pending DE102018100511A1 (en) 2018-01-11 2018-01-11 Rotor blade for wind turbines

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DE (1) DE102018100511A1 (en)

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965753A1 (en) * 1998-06-15 1999-12-22 Dinesh Patel Fluid rotor with spherical vanes
US20040067136A1 (en) * 2002-10-03 2004-04-08 Roberts Frank J. Airfoil assembly
DE60011056T2 (en) * 1999-03-10 2005-07-28 Vind-Och Vattenturbiner Rotor
WO2005108779A2 (en) * 2004-05-03 2005-11-17 Wind Energy Group, Inc. Wind turbine for generating electricity
EP2028102A1 (en) * 2006-03-28 2009-02-25 Zakrytoe Aktzionernoe Obshcestvo "Aviastroitel' Naya Korporatziya 'Rusich' Shpadi propeller (variants) and the involute of the blades thereof
US20090148304A1 (en) * 2007-12-05 2009-06-11 Wagner Thomas V Wind turbine rotor assembly
DE202009012940U1 (en) * 2009-09-24 2010-01-07 Plechl, Anton Monoplan rotor
DE102009038076A1 (en) 2009-08-19 2011-02-24 Konrad Buckel Rotor element for flow around a fluid and rotor
DE102012209935A1 (en) 2011-12-08 2013-06-13 Wobben Properties Gmbh Rear box, rotor blade with rear box and wind turbine with such rotor blade
DE112012005432T5 (en) 2011-12-23 2014-09-04 Korea Aerospace Research Institute Wind turbine with gondola fence

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965753A1 (en) * 1998-06-15 1999-12-22 Dinesh Patel Fluid rotor with spherical vanes
DE60011056T2 (en) * 1999-03-10 2005-07-28 Vind-Och Vattenturbiner Rotor
US20040067136A1 (en) * 2002-10-03 2004-04-08 Roberts Frank J. Airfoil assembly
WO2005108779A2 (en) * 2004-05-03 2005-11-17 Wind Energy Group, Inc. Wind turbine for generating electricity
EP2028102A1 (en) * 2006-03-28 2009-02-25 Zakrytoe Aktzionernoe Obshcestvo "Aviastroitel' Naya Korporatziya 'Rusich' Shpadi propeller (variants) and the involute of the blades thereof
US20090148304A1 (en) * 2007-12-05 2009-06-11 Wagner Thomas V Wind turbine rotor assembly
DE102009038076A1 (en) 2009-08-19 2011-02-24 Konrad Buckel Rotor element for flow around a fluid and rotor
DE202009012940U1 (en) * 2009-09-24 2010-01-07 Plechl, Anton Monoplan rotor
DE102012209935A1 (en) 2011-12-08 2013-06-13 Wobben Properties Gmbh Rear box, rotor blade with rear box and wind turbine with such rotor blade
DE112012005432T5 (en) 2011-12-23 2014-09-04 Korea Aerospace Research Institute Wind turbine with gondola fence

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
BERROTH, Jörg Karl; RWTH Aachen University: Einfluss der Stelldynamik der Rotorblätter auf die Lasten der Blattverstellsysteme von Windenergieanlagen. 1. Aufl.. Aachen : Verlagsgruppe Mainz GmbH, 2017. Deckblatt u. Inhaltsverzeichnis. - ISBN 978-3-95886-180-0. URL: https://dnb.info/1139130552/04 [abgerufen am 2018-05-18]. - Dissertation *
BETZ, Albert: Wind-Energie und ihre Ausnutzung durch Windmühlen. unveränd. Nachdr. d. Orig.-ausg. aus d. Jahre 1926. Staufen : Ökobuch Verlag, 1994. Deckblatt u. Inhaltsverzeichnis. - ISBN 978-3-922964-11-7. *
BILAU, K.: Die Windkraft in Theorie und Praxis – Gemeinverständliche Aerodynamik. Berlin : Verlagsbuchhandlung Paul Parey, 1927. Deckblatt u. Inhaltsverzeichnis. *
CROME, Horst: Handbuch Windenergie-Technik: Windkraftanlagen in handwerklicher Fertigung. 4. Aufl.. Staufen : Ökobuch Verlag, 2012 (Ökobuch magnum). Deckblatt u. Inhaltsverzeichnis. - ISBN 978-3-922964-78-0. URL: http://www.gbv.de/dms/tib-ub-hannover/689343078.pdf [abgerufen am 2018-05-18]. *
GASCH, Robert ; TWELE, Jochen (Hrsg.): Windkraftanlagen: Grundlagen, Entwurf, Planung und Betrieb. 8. Aufl.. Wiesbaden : Springer Vieweg, 2013. Deckblatt u. Inhaltsverzeichnis. - ISBN 3- 8348-2562-x. URL: http://opac.nebis.ch/ead50/objects/view/4/E57_7600722_TBIndex_004487482.pdf [abgerufen am 2018-05-18]. *

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